Pneumothorax in patients with COPD and emphysema receiving home chronic non-invasive ventilation: is it the emphysema phenotype or ventilator setting?

We describe three patients with chronic obstructive pulmonary disease (COPD) and emphysema who developed a pneumothorax while receiving chronic home non-invasive ventilation (NIV). These cases raise the question whether the high alveolar pressures given by NIV may have contributed to the development of their pneumothorax by barotrauma. Pneumothorax in patients with COPD receiving NIV is uncommon, the pressures in our patients with COPD who developed pneumothorax were not extremely high and time to development of pneumothorax was relatively long after the initiation of NIV. Further, in our patients, the CT scan showed paraseptal emphysema, a known risk factor for pneumothorax. This suggests that COPD/emphysema phenotype is probably a more important factor for indicating pneumothorax risk than ventilator settings. Better phenotyping of patients with COPD in whom benefits of NIV can be expected at minimal risk of serious side-effects is needed to inform our patients properly and bring the field of chronic NIV in COPD forward.

The predictive value of an adjusted COPD assessment test score on the risk of respiratory-related hospitalizations in severe COPD patients.

We evaluated whether a chronic obstructive pulmonary disease (COPD) assessment test (CAT) with adjusted weights for the CAT items could better predict future respiratory-related hospitalizations than the original CAT. Two focus groups (respiratory nurses and physicians) generated two adjusted CAT algorithms. Two multivariate logistic regression models for infrequent (≤1/year) versus frequent (>1/year) future respiratory-related hospitalizations were defined: one with the adjusted CAT score that correlated best with future hospitalizations and one with the original CAT score. Patient characteristics related to future hospitalizations ( p ≤ 0.2) were also entered. Eighty-two COPD patients were included. The CAT algorithm derived from the nurse focus group was a borderline significant predictor of hospitalization risk (odds ratio (OR): 1.07; 95% confidence interval (CI): 1.00-1.14; p = 0.050) in a model that also included hospitalization frequency in the previous year (OR: 3.98; 95% CI: 1.30-12.16; p = 0.016) and anticholinergic risk score (OR: 3.08; 95% CI: 0.87-10.89; p = 0.081). Presence of ischemic heart disease and/or heart failure appeared 'protective' (OR: 0.17; 95% CI: 0.05-0.62; p = 0.007). The original CAT score was not significantly associated with hospitalization risk. In conclusion, as a predictor of respiratory-related hospitalizations, an adjusted CAT score was marginally significant (although the original CAT score was not). 'Previous respiratory-related hospitalizations' was the strongest factor in this equation.